1. Field of the Invention
The present invention relates to an actuator which effects linear reciprocating motion of a slider along a frame under a driving action of a driving source.
2. Description of the Related Art
Actuators or the like have been used as transport means for transporting a workpiece.
An conventional actuator is shown in FIGS. 12 and 13 (see, for example, Japanese Laid-Open Patent Publication No. 11-30234).
The conventional actuator 1 includes a slider 4 which is displaceable along a recess 3 of a track rail 2, and a screw shaft 6 which is driven by an unillustrated driving motor and which is screw-engaged with a nut member 5 that is detachable with respect to the slider 4. A pair of screw shaft support members 7a, 7b, which rotatably support the screw shaft 6, are provided at both ends of the screw shaft 6 respectively. The screw shaft support members 7a, 7b are attached to an upper surface 8 of the track rail 2.
However, in the conventional actuator 1, it is not possible to provide the feed screw shaft mechanism as a single assembling unit including the screw shaft 6 and the screw shaft support members 7a, 7b. Therefore, it is not possible to conveniently assemble the feed screw shaft mechanism to the track rail 2 and disassemble the feed screw shaft mechanism from the track rail 2.
Specifically, in the conventional actuator 1, it is necessary to insert the screw shaft 6 through a through-hole 9 of the slider 4 as shown in FIG. 13. Since the slider 4 acts as an obstructive member, it is impossible to provide the feed screw shaft mechanism as a single unit including, for example, the screw shaft 6 and the screw shaft support members 7a, 7b. 
When the screw shaft 6 is assembled to the track rail 2, it is necessary to insert the screw shaft 6 through the through-hole 9 of the slider 4. When the screw shaft 6 is detached from the track rail 2, it is necessary to pull out the screw shaft 6 from an axial end of the track rail 2 to disengage the screw shaft 6 from the through-hole 9 of the slider 4. In such a procedure, when the track rail 2 is fixed, and there is an obstacle at the axial end of the track rail 2, it is difficult to pull out the screw shaft 6 from the through-hole 9 of the slider 4.